1. Field of the Invention
This invention is relates to biologically degradable compositions for medical applications such as for coatings for implantable medical devices.
2. Description of the State of the Art
A wide spectrum of devices, from vascular devices such as catheters, stents, and guidewires, to ocular devices such as intra-ocular lenses is incorporating polymeric material. Polymeric materials are being used for a variety of reasons, including making a surface of a device more biocompatible or as a vehicle for delivering a drug. Since polymeric materials are treated as a foreign object by the body's immune system, the challenge has been to make the polymers highly biocompatible as well as to reduce any fouling effects that the polymer may produce or harbor. As a better option, it may be better to make the polymer not only highly biocompatible and non-fouling, but also biodegradable such that the polymer is eliminated by the body after it has served its function. The degradation of the polymer should not create any residues that can provide adverse effects for the patient, such as excess inflammation. To the contrary, the products of degradation should enhance the treatment that is being provided to the patient or should provide medicinal effects. Should the polymeric material include a drug for local application, the composition should be capable of carrying the drug so as to release the drug at an efficacious rate for a therapeutically effective duration of time. Finally, if the material is used as a coating, the properties of the composition should be suitable so as to allow a film layer to be formed on the medical device. For devices that include body geometry that expand or fold, such as a stent or a balloon, the polymer must be flexible enough so as to expand or fold with the device without significant detachment or delamination of the coating. Tradeoffs do exist between biocompatibility, structural integrity and drug delivery capabilities of the polymer. Enhancing one characteristic may determinately affect the other. Accordingly, a proper balance must be drawn to provide for a polymeric composition that meets the specific need of the application for which it is being used.
The embodiments of the present invention provide for biocompatible polymeric compositions that can be used medical applications.